Expanding structure



Oct, 20, 1.942. H. A. FARRAND EXPANDIING gtrRUTIIJRE' Filed Der; 4, 1941 2 sheets-sheet 2 Patented Oct. 20, 1942 UNITED `STATES ATENT OFFICE EXPANDING STRUCTURE Hiram A. Farrand, Berlin, N. H. Y Application December 4, 1941, Serial No. 421,665

9 claims.

This invention relates to collapsible or expansible structures in accordance with the general principles disclosed in my copending applications Serial No. 262,324, led March 16, V1939, Patent No. 2,269,363, and Serial No. 344,149, filed July 5, 1940, Patent No. 2,269,364; the present case bein-g directed to a specific-application of those general principles in a simple, efficient and economical mechanism not heretofore known to the art. i

As in the instances noted above, thepresent invention relates to devices which are convertible from a longitudinally-extended form, such as a column, beam, strut or other structural support, etc., into a comparatively compact, condensed form, and vice versa, for convenience in transporting from place to place as a mobile emergency or temporary structure, for example, although the structure is also capable of permanent installation in cases where extensibility and contractability of a column, strut, etc., is desired.

In the accompanying drawings:

Fig. l is a side elevation of one form of structure, partly in section, and with an intermediate portion of the extended structure removed for convenience of illustration;

Fig. 2 is a front elevation shown in Fig..1;

Fig. 3 is a transverse sectional plan View taken on the line 3 3, Fig. 2;

Fig. 4 is a top plan View;

Fig. 5 is a` front elevation showing the expansible portion of the structure in a collapsed of the structure, as

state and the lower portion eliminated for conv venience of illustration;

Fig. 6 illustrates a modification with the structure in collapsed form;

Fig. 7 is a plan View of the structure shown in Fig. 6; and

Figs. 8 and 9 illustrate a further modification.`

The device shown in the several figures is a composite structure formed of a plurality of coordinating elements. These elements, taken by themselves, are unable of strain which the composite structure as a whole is calculated to bear;nor will the sum of the individual resistances of the several elements equal the total strength of the combination, which by reason of the assemblage, when once formed constitutes a unit having the characteristics of a trussed structure, wherein strains of a load upon the structure are resisted by means of a lattice and web arrangement throughout the length of the structure, with each part cooperto withstand the amount ating with each other part to its maximum degree of efficiency.

Furthermore, when the elements of the composite structure of the present case are released from their coordinating structure-forming and rigidifyng relationship and become separated, they may be withdrawn from their extended forms and folded and rolled respectively into comparatively compact form for storage or transportation in a condition to be handled conveniently. Likewise, the several parts, on being extended from such compact form, will automatically become reassembledA and retained in theirrespective places in the composite structure as; before. Y

In the structure shown in the several Views of the drawings, two of the component elements la, Ih, are in the form of normally thin rectilinear strips of spring material capable of being distorted. While these strips are straight in theirl longitudinal direction, each is normally of a nonplanar form in itsV transverse direction, i. e., having a cross-sectional shape sometimes referred to as concavo-convex. Each strip is resilient and flexible in all directions, and may be forced out of its normal formation, longitudinally and cross-sectionally by an applied force, but when so forced, will maintain an inherent tendency to return to its normal longitudinally-rectilinear and transversely-non-planar state.

It is to be noted that upon bending in the direction of its length, each strip will flatten out transversely, in the direction of its width, and will only return to its concavo-convex shape when the strip returns to its normally straight longitudinal formation. In the change thus induced, the overall width of the strip increases when the strip is bent longitudinally and only returns to its original lesser width when the strip is permitted to return to its straight normal condition, longitudinally, a fact which is taken advantage of in the winding device illustrated in the drawings for reducing the strips to compact coils.

As is shown in the section, Fig. 3, the strips la, Ib, form the main body of the composite structure and, as such, are placed parallel to each other with their convex faces turned inwardly toward each other in tangential contacting relation to each other at the centers of their curves along the length of the extended structure. The body I, formed of the strips la and Ib, is enclosed within a cage or bracing structure 2 formed or two parallel laterally spaced systems 2d and 2b of pivotally connected links, one system lying along and adjacent the concave face of the strip la and the other along and adjacent the concave face of the strip Ib.

Each system 2a and 2b is formed of successive pairs of crossed links 3a and 3b' pivotally connected at their intersecting centers of rivets, pins, etc., or other fastenings 4, Il. The two relatively spaced system 2a` and 2b are connected across the intervening space occupied by the strips Ia and Iby by hinge pins 5, 5, etc., which also pivotally connect the outer end of the link 3a of one crossed pair with the outer end of' the link 3b of each of the two adjacent pairs of cross links, and thus form a lattice enclosure completely surrounding the strips Ia, Ib. As shown in Fig. 3, the two assembled strips Ia, Ib completely ll the enclosure 6, of the cage 2, with the longitudinal edges I, 'I of the strips respectively seated in the angles formed by the junctures of the link systems 2a, 2b, with the transverse hinge pins 5, 5.

The link systems 2a, 2b, are comparatively rigid with the links thereof pivotally connected throughout each system in a way of permit of folding in a manner to provide for collapse and extension of the system. The links 3a and 3b extend from side to side across the concave face of the adjacent strip, in opposite diagonal directions respectively when in an extended form, as in Fig. 1.

It will be observed that each link system forms a structure, commonly known as a lazy tong, which is capable of rapid extension and collapse by a relatively slight movement of the ends of one pair of cross links toward or away from each other in a direction transversely of the structure.

In Figs. 1 to 5 the top hinge pin 4a, where the upper terminal links 3a. and 3b of each link system cross one another, passes entirely through the structure, including the strips Ia, Ib, thereby anchoring the outer end of each link system to the body structure I at that point. As this is the only connection between the main body structure I, composed of the strips Ia, Ib, and the bracing structure 2, composed of the link systems 2a and L' 2b, the movement of the strips Ia, Ib, up or down, is regulated by the corresponding movements of the anchor pin 4a. Consequently, when the linkage systems 2a, 2b move downwardly in the process of collapsing, the strips Ia and Ib are carried down also, and slide between the link systems 2a, 2b in the cage space 6.

In moving the structure from a collapsed state to a state of extension, it may be operated manually by pulling on the terminal portion of linkage, thus drawing the extensible and collapsible structure I--2 out to its complete extension. Mechanical means to accomplish the same purpose, which may be applied to large units employed in structural work, and which also locks the structure in whatever position of extension or collapse is desired, is shown in Figs. 1, 2, 4 and 5.

In Figs. l and 2, the upper terminal pairs of links 3a and l) are modified to form obtuse angles and the two systems 2a and 2b, at either side, are joined together by means of cross-blocks 8,8, from the opposite ends of which the hinge pins 5a, 5a of the angularly-disposed terminal ends of the links 3a and 3b extend.

Each of the blocks 3,8 is bored transversely. One of the bores thus formed is provided with a right-hand screw thread, while the bore in the other block is provided with a left-hand screw thread. Passing through the threaded bores of 73 both of the blocks 3,8 is an operating and locking screw 9, which is provided with right and lefthand threads 9a. and 9b, respectively, to match those of the blocks 8,8. The blocks 8,8 are spaced equally with respect to the longitudinal axis of the structure I-2 in such manner that rotation of the screw shaft 9 in one direction draws the two blocks 8,8 together and, when turned in the opposite direction, forces the two blocks apart.

By turning the screw shaft 9, by a key or crank applied to a squared or other splined end 9c thereof, shown in Fig. 2, the structure may, by reason of the pivotally connected link systems 2a and 2b, be extended or collapsed and locked against accidental change.

The usefulness of the structure as a support is afforded by the component parts of the structure being correspondingly extended axially of the structure by the components being retained in rm contact with each other, so that a load strain applied to any part of the composite structure, due to the full cooperating and coordinating relationship of the component parts, each with each other, will be distributed uniformly throughout the composite structure.

When the extension is reduced, the distance between hinge pins 5a, 5a, laterally, is increased, and the linkage systems guide the strips in their downward movement. The inherent stiffness of the strips prevent their buckling within the confines of the cage formed by the links.

The lower end of the composite structure I-2 is, as shown in Figs. l and 2, held in frame members I2,I2 of a base structure II), to which the lower terminal links 3a and 3b of the linkage systems 2a and 2b are movably anchored, The lower pairs of links of the two systems 2a, 2b are joined, across the space 6, by hinge pins 5b, 5b, which pass through and extend beyond the links and project into horizontal slots I3,I3, provided in the frame members I2,I2. lThe lengths of the slots I3 are such as to provide for full horizontal movement of the pins 5b, 5b, when the structure I-Z, described above, passes from full extension to'complete collapse.

The frame members IZ,IZ, are attached on either end to side plates or frame members I4,I4, which also serve to support a pair of winding reels Ita, |612. The frame plates I4,I4 are held in proper relation to one another by transverselyextending stay rods I5,I5, which pass through the housing from side to side.

The construction and operation of the reels Mia., Iib correspond to the reels described in my prior U. S. Patent No. 2,056,844, dated October 6, 1936, which is directed to a Transmission mechanism. As shown in Figs. l5 and 16 of said patent, the reel operates automatically to wind up a resilient concave-convex strip whenever the strip is pushed longitudinally toward it, in a position tangential to the coil. It also allows the concavoconvex spring strip to unwind automatically from such coil when not held in restraint.

The strips Ia, Ib are respectively attached separately to the reels ISa, Ib, and owing to the particular construction of the reels, the side flanges thereof are of greater diameter than the f coils wound on the reel-drums. For this reason, the reels are staggered in position to receive the respective strips tangentially to the peripheries of the drums, or the outermost convolutions of the coils wound on the drums.

While the device for locking the extensible structure is shown in the present instance as being in the form of a single screw 9, I do not wish to so limit my invention, because any number of simple Well known equivalent locking devices may be employed, such as a hook or latch, Without departing from the spirit of my invention.

In Figs. 6 and 7, the operating mechanism for extending and collapsing the structure I2 is shown as being operated from the base frame I0. The hinge pins 5b, 5b, in this instance, extend beyond the frame member I2, I2, and are secured at their opposite ends to screw blocks 8a, 8a, which are respectively threaded onto operating and locking screw shafts 9d, 9d, each of which is provided with right and left-handed screw threads operating in corresponding threads formed in the bores of said blocks. l

The screw shafts 9d, 9d are provided with synchronizing means, such as intermeshing gears II, II, whereby said screw shafts will rotate together and operate the screw block 8a,

8a in unison for extending or collapsing the link systems 2a and 2b simultaneously.

As in the case of Figs. l and 5, where `the pivot pin ,da anchors the link systems 2a, 2b to the main body structure I composed of the strips i Ia, I b, the pivot pin 4b in Figs. 6 and 7, serves the same identical purpose.

In the modication shown in Figs. 8 and 9, a single concavo-convex strip Ic and a single lazy tong structure 2c are coordinated to form the complete composite structure, with the linkage system 2a located adjacent the concave face of the strip lc.

In the linkage system 2c, the opposite outer ends of one link of each crossed pair of links, or one outer end of each link of each pair, are bent into the form of a hook 5c to engage and to extend across and around the outer opposite longitudinal edges respectively of the strip Ic, when the strip Ic and linkage system 2c are each fully extended, to rigidify the structure as a whole.

In the above case, the strip I c and the linkage system 2c, when not coextensively arranged in the complete extended composite structure, may

be completely separated and stored, etc. To complete the extended structure the strip Ic may be permitted to assume its normal rectilinear form. The linkage system, in collapsed form,

lmay be laid on the concave face of the strip Ic and then extended along the strip. The opposite end terminals of the linkage system may then be anchored to the opposite ends respectively of the strip, as by removable bolts or pins,

etc., 4c, 4c.

The strips Ia, Ib, and lc have been described as having a normally concavo-convex cross-sectional form which is adapted to be changed to a fiat planar cross-section when the strip is rolled for storing, etc. cross-sectional shape of the strips may be substantially flat, or only slightly bowed, with the strips being capable of a wide range of transverse flexure into concavo-convex cross-sectional forms with the cord and height of the segment of the cross-section varying with the longitudinal extension of the structure as a Whole, without departing from the spirit of the invention. In such cases the cross pivots 5, or the hooks 5c, or mechanical equivalents for the cross pivots or the hooks in the form of rollers, for example, would remain in contact with the longitudinal edges of the strips throughout the entire range of extension and contraction thereof, and the composite structure under such circum- Conversely, the normal stances would he capable of supporting a load at any stage of its longitudinal extensibility. i

I claim:

l. A composite structure comprising a thin strip of flexible longitudinally-coilable `material capable of ychange in its cross-sectional form from a transversely-nat to a transversely-curved state, and vice versa, a system of pairs of crossed links adjacent one face of the strip, means pivotally connecting the links of each pair at their point cf crossing, means pivotally connecting the links of successive pairs at points outwardly spaced from said crossing point pivots, and means coaxial with said outer pivots for engaging the longitudinal edgesA of said strip to 'retain the strip in a longitudinal rectilinear form.

2. A composite structure comprising a thin strip of flexible longitudinally-coilable material, a series of pairs of crossed links, means pivotally connecting the links of each pair at thei` crossing point, means pivotally connecting the links of successive pairs at points spaced outwardly from said crossing points, and means connected to predetermined links adjacent said outer pivots for engaging the longitudinal edges of the strip to retain the strip therebetween against distortion from a longitudinally-rectilinear form.

3. A composite structure comprising a thin strip of flexible longitudinally-coilable material of concavoconve`x cross-vsectional form, a series of pairs of crossed links adjacent one face of the strip, means pivotally connecting the links of each pair at their crossing point, means pivctally connecting the links of successive pairs at points spaced outwardly from said crossing points, and means connected to predetermined links adjacent said cuter pivots for engaging the longitudinal edges of the strip to retain the strip therebetween against distortion from a longitudinallyrectilinear form.`

4. A composite structure comprising a thin strip of flexible longitudinally-coilable material of concavo-convex cross-sectional form, a series of. pairs of crossed links adjacent the concave face of the strip, means pivotally connecting the links of each pairat their crossing point, means pivotally connecting the links of successive pairs at points spaced outwardly from said crossing points, and means connected to predetermined links adjacent said outer pivots for engaging the longitudinal edges of the strip to retain the strip therebetween against distortion from a longitud'inally-rectilinear form.

5. A composite structure comprising a parallel pair of longitudinally-rectilinear strips of concavo-convex cross-section arranged with the convex faces thereof contacting along the longitudinal centers thereof, a series of pairs of crossed links adjacent and coextensive with the concave face of each strip, means connecting the crossed links of said pairs along the longitudinal centers of said systems respectively, and means connecting the outer ends of the crossed links of successive pairs in each system to each other and to the corresponding ends of the corresponding links of the other of said systems along and adjacent the opposite longitudinal edges respectively of said parallel strips.

6. A composite structure comprising a parallel pair of longitudinally-rectilinear strips of concavo-conVeX cross-section arranged with the convex faces thereof contacting along the longitudinal centers thereof, a series of pairs of crossed links adjacent and coextensve With the,

concave face of each strip, means pivotally connecting the crossed links of said pairs along the longitudinal centers of said systems respectively, transversely-extending means pivotally connecting the outer ends of the crossed links of successive pairs in each system to each other and to the corresponding ends of the corresponding links of the other of said systems along and adjacent the opposite longitudinal edges respectively of said parallel strips, and means for maintaining said systems in longitudinally-extended condition with the longitudinal edges oi the strips respectively seated in the angles formed by said transversely-extending means and the links of said systems.

7. A composite structure comprising a parallel pair of longitudinally-rectilinear strips of concavo-convex cross-section arranged with the convex faces thereof contacting along the longitudinal centers thereof, a series of pairs of crossed links adjacent and coextensive with the concave face of each strip, means pivot-ally connecting the crossed links of said pairs along the longitudinal centers of said systems respectively7 transversely-extending means pivotally connecting the outer ends of the crossed links of successive pairs in each system to each other and to the corresponding ends of the corresponding linksof the other of said systems along and adjacent the opposite longitudinal edges respectively of said parallel strips, and means pivotally connected to the outer ends of one of the pairs of links of each system for moving said outer ends toward and away from each other trans- Versely of said strips to effect pivotal movement between the links of each crossed pair in each system simultaneously for collapsing and extendingsaid linkage systems longitudinally of said strips.

8. A composite structure comprising a parallel pair of longitudinally-rectilinear strips of concavo-convex cross-section arranged with the convex faces thereof contacting along the longitudinal ce'nters thereof, a series of pairs of crossed links adjacent and coextensive with the concave face of each strip, means pivotally connecting the crossed links of said pairs along the longitudinal centers of said systems respectively, transversely-extending means pivotally connectingr the outer ends of the crossed links of successive pairs in each system to each other and to the corresponding ends of the corresponding links of the other of said systems along and adjacent the opposite longitudinal edges respectively of said parallel strips, means pivotally connected to the outer ends of one of the pairs of links of each system for moving said outer ends toward and away from each other transversely of said strips to eiect pivotal movement between the links of each crossed pair in each system simultaneously for collapsing and extending said linkage systems longitudinally of said strips, and means connecting the center pivot of one pair of crossed links in each system to said strips to maintain a predetermined relationship between said systems and said strips during extension and contraction of the structure as a whole.

9. A composite structure comprising a parallel pair of longitudinally-rectilinear strips of concavo-convex cross-section arranged with the convex faces thereof contacting along the 1ongi-` tudinal centers thereof, a series of pairs of crossed links adjacent and coextensive with the concave face of each strip, means pivotally connecting the crossed links of said pairs along the longitudinal centers of said systems respectively, transversely-extending means pivotally connecting the outer ends of the crossed links of successive pairs in each system to each other and to the corresponding ends of the corresponding links of the other of said systems along and adjacent the opposite longitudinal edges respectively of said parallel strips, means pivotally connected to the outer ends of one of the pairs of links of each system for moving said outer ends toward and away from each other transversely of said strips to effect pivotal movement between the links of each crossed pair in each system simultaneously for collapsing and extending said linkage systems longitudinally of said strips, means connecting the center pivot of one pair of crossed links in each system to said strips to maintain a predetermined relationship between said systems and said strips during extension and contraction of the structure as a whole, and` means for coiling said strips during collapsing of said structure as a whole.

HIRAM A. FARRAND. 

